This study evaluates RNFL Birefringence in normal and glaucoma human subjects: The primate experimental glaucoma study will characterize the spatial and temporal dynamics of RNFL birefringence during glaucoma progression and establish an initial feature set and classifier for a case-control clinical study. The case-control clinical study will refine the initial feature set and classifier and use ROC analysis to test sensitivity and specificity of the feature set and classifier for discriminating between normal and glaucomatous human eyes. The feature set and classifier formulated in the case-control clinical study is a prerequisite for planning a large-scale longitudinal study. A large-scale longitudinal study to compare different approaches for detecting early glaucoma is outside the scope of the proposed research. Moreover, considering the large number of subjects required for statistical significance when the conversion rate from ocular hypertensive to glaucoma is low (<10%/year), a longitudinal study is best performed in a multi-institution clinical trial over several years.